Update URL for downloading HDF5 during Travis pull request runs. A new release of HDF5 caused the old URL to become non-existent.
Update URL for downloading HDF5 during Travis pull request runs. A new release
of HDF5 caused the old URL to become non-existent.

paulromano/openmc,wbinventor/openmc,mit-crpg/openmc,shikhar413/openmc,shikhar413/openmc,mit-crpg/openmc,wbinventor/openmc,smharper/openmc,amandalund/openmc,shikhar413/openmc,paulromano/openmc,liangjg/openmc,johnnyliu27/openmc,paulromano/openmc,walshjon/openmc,amandalund/openmc,wbinventor/openmc,bhermanmit/openmc,kellyrowland/openmc,liangjg/openmc,shikhar413/openmc,samuelshaner/openmc,wbinventor/openmc,johnnyliu27/openmc,johnnyliu27/openmc,johnnyliu27/openmc,samuelshaner/openmc,mjlong/openmc,walshjon/openmc,mit-crpg/openmc,smharper/openmc,liangjg/openmc,lilulu/openmc,samuelshaner/openmc,smharper/openmc,samuelshaner/openmc,mjlong/openmc,lilulu/openmc,smharper/openmc,mit-crpg/openmc,kellyrowland/openmc,amandalund/openmc,amandalund/openmc,liangjg/openmc,walshjon/openmc,bhermanmit/openmc,lilulu/openmc,walshjon/openmc,paulromano/openmc